Starting or working at a start-up can be one of the most stressful things a person does in his or her life.
Despite the fact that thousands have done it all before, it can be daunting to take your first step without a mentor as a guide.
Thankfully, the social question-and-answer site Quora has a Start-up Advice and Strategy section, which is full of awesome entrepreneurs and venture capitalists who want to help others learn from their mistakes and accomplish their goals.
We've searched through them and pulled out the very best advice that founders have given to help others be successful.
-- Kyle RussellThis story originally appeared on Business Insider.

Tim Westergren, founder of Pandora

Learn public speaking.
Of all the skills that an entrepreneur can have, I think the ability to convey an idea or opportunity, with confidence, eloquence and passion is the most universally useful skill. Whether you're pitching a group of investors, rallying your employees, selling a customer, recruiting talent, addressing consumers, or doing a press tour, the ability to deliver a great talk is absolutely invaluable. And it is perhaps the most under-recognized and under-nurtured skill.

Dan Cristo, founder of Triberr

You know how they always say, "Dress for the job you want, not the job you have"? I say, "Do the job you want, not the job you have."
Your ideal job probably requires skills and experience you can't get in your current role. Go ahead and learn those skills outside work through side projects or volunteering. Then bring these new skills into your current role. This is my core principal of job advancement.

Farhad Meher-Homji, founder of Brightlabs

Just because you trust someone, doesn't mean you can depend on them as well. Trust and delivery can be two different things.

Saul Klein, founder of Kano Computing

The perfect start-up has all three founders:
- Someone who understands how to build technologies and systems to solve problems
- Someone who understands the human factors behind those problems, why they exist, what it takes to fix them and how to shape the experience
- Someone who understands how to reach, talk to and sell to the people whose problems are being solved--and keep finding more of them
The ideal start-up has two of the three founders, but all three skills are present between them.

Michael Wolfe, CEO of Pipewise

Pick where you want to live and the people you want to hang out with first.
Then find a career that lets you do that.

Edmond Lau, early engineer at Quora

When I interned at Microsoft the summer of my junior year in college, I received a good piece of advice secondhand from a friend's mentor: always re-examine and reflect on where you are in your career at least every two years. Even if you're perfectly happy with your job, the exercise forces you to check that you are actually enjoying your work and learning on the job rather than just being comfortable.

Phineas Barnes, partner at First Round Capital

Know that there are three choices you get to make and the rest is heavily influenced by circumstance and luck. You choose your idea. You choose your business partners. You choose your investors. Your choice of partners and investors should be thought of as permanent and are therefore the most important two decisions you make. The idea can change and evolve but this ability and the direction of this evolution will be highly influenced by your choice of partners and investors.

Chris Prescott, founder and CEO of Fantasy Shopper

Learn to say no.
In the early months, you'll be in hustle mode and will likely be saying 'yes' to every opportunity, getting whatever and whoever you can to help with momentum. Assuming all goes well, you'll reach a tipping point where people start coming to you instead of you going to them--be that speaking events, trial services, coaching, investment etc etc. You will no longer have the time or need to say "yes" to everything, so get the confidence to start saying "no" to stay focused on your vision.

Peter Berg, founder of October Three, currently on Visa's innovation team

Be really picky with your hiring, and hire the absolute best people you possibly can. People are the most important component of almost every business, and attracting the best talent possible is going to make a huge difference. Quality and quantity of output is not linear (e.g. one rockstar programmer can produce much better code than two average or slightly below average programmers). Throwing more people at a problem doesn't necessarily solve it faster, but it definitely costs more. So hire the best people. (And if you make a mistake, don't be afraid to let them go.)

Mark Otero, founder and CEO of KlickNation

Fail fast: Start with a working set of assumptions and test them out in the market very fast. If your assumptions are wrong then pivot, adjust, and make a decisive decision. Remember, entrepreneurs love the process, the idea is one of many you'll have to achieving greatness, and commercial success.
Know your weaknesses: Knowing your weaknesses is as important as knowing what your strengths are, and even more important as your company grows; hire or have co-founders who are great in areas where you are weak.

John Lilly, partner at Greylock Partners

All advice you get about your start-up might be totally, completely wrong. Also, it all could be absolutely, 100% right. No matter what the source, no matter how expert or accomplished the advisor. Start-ups, like any organization, exist and thrive despite a million totally plausible reasons that they shouldn't.
Great entrepreneurs seek help and advice from as many sources as they possibly can, figure out how to make use of some and discard the rest. But every successful start-up looks different; every one will have pieces of advice they hold to be absolutely true--and lots of times other very successful start-ups will know that same piece of advice to be dumb and useless.
Ask for advice. Listen. But make your own way.

Jeremy Liew, partner at Lightspeed Venture Partners

"Never give up"--and its variants--is often bad advice. It can certainly help provide some grit during the tough times, but many start-ups find that life is pretty easy when things are going well, and the converse is also true. If it's hard, you may be doing something wrong. Working harder is usually not the solution (actually working harder is usually the solution for when things are going well). Doing something differently (up to and including giving up and trying something else) is usually the right answer if it just feels all too hard and has done for a long time
Some start-ups are successful after long periods of failure, but they are few and far between. It's tough to turn around momentum, and many of the wildly successful start-ups saw real momentum early on, with challenges largely around scaling gracefully, not around getting momentum in the first place.

John Seiffer, founder of CEO Boot Camp

Advice about the power of passion is wrong. Of course you have to be passionate--why else would you work those crazy hours and blow all that money. But the people whose companies crashed and burned were passionate too.
Consider interviewing people who've been married for 50 years. I bet they'll all say they're in love. But so will the people who've been married 2 weeks and will divorce in the next 2 years.
Or you know that movie about the guy who sacrifices everything building a landing platform for space aliens in his living room? He looses job, wife, kids yet still goes at it. Then at the end the aliens come to get him and they are friendly, super intelligent etc. Well, guess what? They don't make movies about the guys who loose everything building a landing platform but in the end, the aliens don't come--he just dies homeless under a bridge. Lousy movie but happens more often in real life.

Jon Davis, employee at Quora and owner of a private real estate firm

Fill out the application.
Because sometimes your fears of opportunity are the only actual thing preventing you from getting your dream job, that business loan or a new home. Sometimes you sit and look at the jobs website a dozen times thinking that you don't want to face the fear of rejection and you never do it. Sometimes you think to yourself that if they were to hire you, you would surely fail. Sometimes you think about the change in your life and what it might mean. Sometimes you might turn out to be more scared of the change than you are with the situation you want so badly to change. This is why you are still there asking what is good advice for your career.
Sometimes the best things in life are huge and terrifying, different and drenched with change, but they require you to take that step in the middle of one night. You click that button, fill out that form, make the call, send the email. Take the chance, take the risk and fail. Fail until you finally get the call back, which never comes to the very scared person who never filled out the application.

Hassan Baig, founder of White Rabbit Studios

"Invest time in a 'scalable' career." -- Nassim Nicholas Taleb
This isn't advice I received first-hand, but nevertheless I think it qualifies as an answer to this question.
A "scalable" career is one where growth is not dependent on the number of hours of work put in. For instance, imagine you're a tax consultant. You probably charge an hourly rate for your consultative services. This of course implies that every marginal hour of work you put in generates value at that very margin. In other words, you're selling your time--which unfortunately you have only 24 hours of per day. Such a career would be naturally tough to scale up.
So what's the alternative? It is picking a career for yourself where growth is dependent on the quality of your decisions. This philosophy ensures you're monetizing your intellect/foresight/pattern recognition skills instead of your time, and can thus generate really high pay-offs (provided you can get it right).

Joshua Ledgard, founder of KickoffLabs.com

Succeed (or fail) at someone else's (well funded) startup.
Within the product teams at Microsoft I learned a ton about shipping software and managing people, but it didn't expose me to the business and marketing site of the coin much. The downside of a larger company is the unintentional silos that go up.
I tried to find job internally that was both a promotion and would start exposing me to those things. When I couldn't find it ... I left and joined a <100 person company.
They were crazy enough to let me:
- Run my own team.
- Manage the budget and revenue for this team.
- Work closely with sales, marketing, and consulting aspects of the business.
- See just how important customer support is to the success of a startup that wants to make money.

Jared Kim, founder and CEO of Forge

Contrary to the stereotype, startups are a marathon, not a sprint.
The truth is, you are not going to be a billion dollar company or acquired in the next 18 months. This shit takes a long time.
Surround yourself with people you will want to work with for the next 5 years and beyond (e.g. co-founders, employees, advisors, board members, investors, etc).
Don't burn out. Take care of yourself by getting 8 hours of sleep, eat healthy, and exercise. If you don't take care of yourself, there's no way you can take care of your company in the long-term. Obviously there will occasionally be the special circumstances that will prohibit you from keeping a normal schedule (e.g. the days leading up to launch), but make those days the exceptions not the norm.